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AIR  ENGINE  COMPANY. 


INCORPORATED  UNDER  THE  LAWS  OF  THE  STATE  OF  NEW  HAMPSHIRE. 


CAPITAL  STOCK,  $1,000,000. 

10,000  SHARES. 


2000  SHARES  PREEERRED  STOCK. 
8000  SHARES  COMMON  STOCK. 


DIRECTORS. 

JAMES  A.  WOODBURY.  JOSHUA  MERRILL.  GEORGE  PATTEN. 
E.  FRANK.  WOODBURY.  GEORGE  A.  KEELER. 

JAMES  A.  IVOODBURY,  President.  HIRAM  M.  GOODRICH,  Clerk. 

JOSHUA  MERRILL,  Treasurer.  E.  FRANK.  WOOIIBURV,  Constmcting  Engineer. 


Counsel  for  tloe  Compeiny. 
CH.\RI.ES  C.  MORG.AN,  32  Pemberton  Square,  Boston. 


OEEICES. 

No.  2 Goodrich  Block,  | No.  8 Exchange  Place, 

NASHUA,  N.  H.  BOSTON,  MASS. 


Digitized  by  the  Internet  Archive 
in  2017  with  funding  from 
Columbia  University  Libraries 


https://archive.org/details/treatiseOOwood 


Kxgine 


Cox'ererl  by  aii(  l Eipplicatic  )iis  f(  )r  F*£iteot«, 

iiT^  tbe  LJiiitecl  St/ites,  Ca.iiacla,  and  Ktirope. 


PATENTS  GRANTED  BY  THE  UNITED  STATES  OF  AMERICA. 


Xo. 

228712. 

Dated 

June 

8, 

1880. 

Xo. 

of 

Claims, 

^4 

No. 

228713. 

Dated 

June 

8, 

1880. 

No. 

of 

Claims, 

10 

Xo. 

228714. 

Dated 

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8, 

1880. 

Xo. 

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7 

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1880. 

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1880. 

Xo. 

of 

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20 

Xo. 

228717. 

Dated 

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1880. 

Xo. 

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6 

Xo. 

289484. 

Dated 

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1883. 

Xo. 

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-) 

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289485. 

Dated 

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1883. 

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324060. 

Dated 

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1885. 

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Dated 

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324062. 

Dated 

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1885. 

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325640. 

Dated 

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I, 

1885. 

No. 

of 

Claims, 

1 1 

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327748. 

Dated 

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6, 

1885. 

Xo. 

of 

Claims, 

0 

Xo. 

331359- 

Dated 

Dec. 

I, 

1885. 

No. 

of 

Claims, 

a 

Xo. 

331360. 

Dated 

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1885. 

No. 

of 

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331361. 

Dated 

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I, 

1885. 

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16, 

1886. 

No. 

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Claims, 

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404i4(f 

Dated 

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28, 

1 889. 

No. 

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162 


X REATISE. 


In  submitting  this  treatise  we  trust  that  the  presentation  of  this  subject 
will  command  the  attention  of  all  users  of  motive  power. 

Appended  to  the  treatise  will  be  found  a series  of  illustrations ; the  testi- 
monials of  the  firm  of  Messrs.  Hancock  & Allen,  who  have  used  one  of  our 
experimental  engines  in  the  driving  of  their  works  at  Winchendon,  Mass.,  for 
five  years ; the  Expert  Report  of  George  H.  Barrus,  relative  to  a 35  Horse 
Power  Engine  on  exhibition  at  the  works  of  the  Downer  Kerosene  Oil  Co.,  at 
South  Boston ; the  opinions  of  several  Engineers  as  to  the  value  of  the  Engine ; 
and  quotations  from  various  authorities,  with  explanatory  notes. 

Any  information  concerning  our  engine,  we  will  with  pleasure  impart. 

James  A.  Woodbury. 

Joshua  Merrill. 

Inventors. 

George  Patten. 

Edward  F.  Woodbury. 


Boston,  1889. 


Superiority  of  the  Engine. 


Tlic  essential  features  of  our  engine  are  a heater,  regenerator,  and  cooler,  which  three 
in  combination  are  termed  a reverser.  The  engine  illustrated  is  com])o.sed  of  two  reversers 
and  two  double  acting  working  cylinders.  It  is  not  an  e.xhausting  engine,  therefore,  it  has 

neither  admission  nor  exhaust  valves.  It  is  claimed  to  be  the  best  motor  ever  produced, 
for  the  following  reasons:  — 

It  is  absolutely  safe. 

It  is  simple  in  construction. 

It  is  noiseless  in  operation. 

It  is  durable  and  well  arranged  in  all  its  parts. 

It  is  constant  in  its  speed. 

It  is  made  from  improved  designs  and  new  patterns. 

It  is  made  of  the  best  materials,  in  the  most  workmanlike  manner. 

It  is  economical  in  its  operation,  requiring  one-half  less  fuel  than  any  other  engine. 

It  is  interchangeable  in  all  its  wearing  or  working  parts,  therefore,  duplicate  parts  can 

be  immediately  supplied. 

It  is  perfectly  lubricated  at  less  expense  than  any  other  engine,  requires  the  minimum 

amount  of  attention,  it  occupies  less  room,  and  it  costs  no  more  than  a steam,  gas,  or  any 
other  style  of  engine  plant  of  the  same  power  and  workmanship. 

The  expense  to  the  inventors  in  working  up  the  engine  to  its  present  perfected  state, 
has  been  the  expenditure  of  Si 50,000.  in  cash,  and  twelve  years  of  their  time.  It  may  be 

projierly  stated  at  this  time,  that  our  action  in  delaying  the  introduction  of  our  engine  has 

been  the  subject  of  criticism  ; but,  it  has  been  deemed  advisable  by  us,  though  at  great 

personal  present  loss  and  discomfort  to  perfect  the  engine  at  our  expense,  rather  than  at  the 

expense  of  the  public.  The  engines  made  by  us  to-day  are  more  than  twice  as  practical, 

durable,  and  economical  as  the  engines  made  six  years  ago,  nevertheless,  the  engine  sold  to 
Ozro  Hancock,  ICsq.,  made  about  six  years  ago,  has  given  him  and  his  successors,  IMessrs. 

Hancock  & Allen,  the  greatest  of  .satisfaction  during  a run  of  five  years.  See  appended 

testimonial. 

CONSTRUCTION. 

The  illustrations,  represent  our  35  Horse  Power  Ifngine.  P'igure  i is  an  elevation, 

figure  2 is  a plan,  and  figure  3 is  a vertical  sectional  view  of  one  reverser  and  working 

cylinder.  The  reversers  are  in  duplicate,  so  also  are  the  working  cylinders. 

Plach  reverser  is  provided  with  a reverser  heater,  placed  within  a furnace  ; a regenerator, 
composed  of  wire  cloth  of  great  superficial  area,  extending  from  the  cooler  to  the  bottom 

of  the  reverser  heater ; a cooler,  composed  of  a large  number  of  thin  copper  tubes,  which 

are  surrounded  by  water ; and  a displacer  piston,  having  metallic  jiacking  rings,  and  adapted 

to  reciprocate  within  the  cooler.  Each  working  cylinder  is  provided  with  a working  piston 

having  metallic  packing  rings.  Each  reverser  is  connected  by  means  of  pipes  with  the  working 


cylinders,  as  follows  : — The  hot  chamber  below  the  displacer  piston  is  connected  with  the 
bottom  of  the  working  cylinder  directly  opposite ; and  the  cold  chamber  above  the  displacer 
piston  is  connected  with  the  top  of  the  working  cylinder  diagonally  opposite. 

The  means  employed  of  converting  the  reciprocating  motion  of  the  pistons  into  a rotating 
motion  are  all  of  a common  type. 

A small  single  acting  air  pump,  having  a leather  packed  piston,  is  operated  by  an  eccentric 
fastened  to  the  main  shaft.  This  pump  is  used,  first ; to  compress  the  air  to  the  initial  pressure 
required,  second ; to  maintain  the  initial  pressure  so  attained,  which  is  subjected  to  loss  bv 
leakage  around  the  piston  rods,  which  are  packed  in  a very  cheap,  durable,  and  efficient  manner, 
by  means  of  cup-shaped  leather  packings. 

The  regulation  of  the  speed  of  the  engine  is  obtained  by  a balanced  equalizing  valve  of 
simple  construction,  placed  in  an  equalizing  pipe  which  connects  the  top  of  the  working  cylinders 
together.  The  valve  being  operated  by  a common  centrifugal  governor. 

OPERATION. 

The  power  produced  is  due  to  the  energy  exerted  upon  the  working  pistons,  by  the  alternate 
raising  and  lowering  of  the  temperature  of  the  same  mass  of  air  within  the  reversers. 

When  sufficient  heat  has  been  imparted  to  the  reverser  heaters,  by  the  combustion  of  any 
kind  of  fuel  within  the  reverser  furnaces,  the  engine  may  be  started  by  the  use  of  compressed 
air  (previously  compressed  into  a small  reservoir)  admitted  into  the  engine  in  an  alternate  manner, 
similar  to  the  starting  of  a Corliss  engine,  by  means  of  starting  valves,  (two  common  lever  or 
globe  valves).  This  method  of  starting  is  employed  in  engines  of  large  sizes,  or  when  it  is 
desired  to  start  an  engine  under  a load.  Engines  of  small  sizes  may  be  started  as  above,  or  by 
the  use  of  a starting  lever  applied  to  the  rim  of  the  fly  wheel,  or  by  giving  the  fly  wheel  a 
one-half  turn. 

The  cooling  medium  used  is  any  kind  of  water,  or  a blast  of  air  circulated  through  the 
coolers.  A very  small  quantity  of  water  is  required,  and  the  same  body  of  water  may  be  used 
over  and  over  again. 

DETAILED  DESCRIPTION  OF  OPERATION. 

In  the  operation,  the  alternate  raising  and  lowering  of  the  temperature  of  the  same  mass 
of  air  is  accomplished  as  follows:  — In  the  upward  stroke  of  the  displacer  piston,  the  mass  of  air 
in  the  cold  chamber  above  the  piston  is  forced.  Frst,  through  the  cooling  tubes,  in  its  downward 
passage,  through  which  the  temperature  of  the  air  is  not  materially  changed.  Second,  the  air 
enters  the  regenerator,  and  in  its  passage  through  the  same  it  absorbs  heat  which  has  been 
imparted  to  the  regenerator.  Third,  the  air  then  passing  over  the  heated  surface  of  the  reverser 
heater,  thereby  becoming  further  heated,  enters  the  hot  chamber  Ijelow  the  displacer  piston. 

The  temperature  of  the  air  in  the  cold  chamber  is  about  120°  F.,  and  the  temperature  of 
the  air  in  the  hot  chamber  is  about  600°  F. 

In  the  downward  stroke  of  the  displacer  piston,  the  mass  of  air  is  forced.  First,  to  the 
regenerator.  Second,  the  air  enters  the  regenerator,  and  in  its  passage  through  the  same,  it 
deposits  thereon  the  greater  portion  of  its  heat.  Third,  through  the  cooling  tubes,  where  its 


tcm[)crature  is  rctluced  to  aliout  120°  I'.,  and  tlion  into  the  cold  chainl^cr  above  tlie  disiilacer 
piston.  Therefore,  at  each  upward  and  downward  stroke  of  the  displacer  ])islon.  the  temperature 
of  the  same  mass  of  air  is  alternately  raised  and  lowered.  The  reversers  bein;;'  in  duplicate,  it 
is  obvious  that  the  same  alternate  raising  and  lowering  of  the  temperature  of  the  displaced  air 
would  take  place  in  one  reverser  as  in  the  other;  but,  at  o])posite  times;  that  is  to  sav,  both 
displacer  pistons  being  ojierated  b)'  the  reverser  beam,  whenever  one  displacer  piston  is  making 
its  upward  stroke,  the  other  displacer  jiiston  is  making  its  downward  stroke.  It  is  therefore 
evident,  that  when  the  disj^laced  air  in  one  reverser  is  being  heated,  the  disjilacetl  air  in  the  other 
reverser  is  being  cooled. 

The  alternate  raising  and  lowering  of  the  temperature  of  the  displaced  air,  (in  both  re- 
versers) generates  a jiower  in  accordance  with  the  well-known  laws  of  the  e.xpansion  of  gases, 
which  iiower  is  developed  by  the  working  cylinders,  as  follows;  — While  one  displacer  piston  is 
making  its  upward  stroke,  and  is  heating  and  exi)anding  the  displaced  air,  thereby  producing  a 
pressure  which  is  exerted  against  the  bottom  of  the  working  piston  of  the  working  cylinder 
directly  oj^posite  the  reverser,  and  against  the  top  of  the  working  piston  of  the  working  cylimler 
diagonally  opposite  ; the  other  displacer  piston  is  making  its  downward  stroke,  and  is  cooling  and 
contracting  the  displaced  air,  thereby  reducing  the  pressure  against  the  bottom  of  the  working 
piston,  of  the  working  cylinder  directly  opposite  the  reverser,  and  the  top  of  working  piston  of 
the  working  cylinder  diagonally  opposite.  Thus  each  working  piston  is  subjected  to  differential 
pressures,  which  are  alternately  reversed  as  the  displaced  air  is  alternatelv  heated  and  cooled. 
Thus  a power  is  exerted  to  cause  the  working  pistons  to  have  a reciprocating  motion,  which  is 
changed  to  a rotary  motion  by  means  of  the  working  cylinder  beam  and  its  connected  parts  to 
the  main  shaft  and  the  fly  wheel,  from  which  the  power  may  be  taken  off  b}'  a belt.  A por- 
tion of  the  power  developed  is  absorbed  in  the  friction  of  the  engine,  and  a portion  is  used  to 
operate  the  displacer  pistons,  by  means  of  a reverser  crank,  reverser  connecting  rod,  side  lever, 
trunnion,  reverser  beam,  and  connected  parts.  The  engine  is  designed  to  run  on  an  initial 
pressure  (per  gauge)  of  air  of  about  forty-five  pounds,  at  a speed  of  115  revolutions  j^er  minute. 

At  each  revolution  of  the  engine  the  cpiantity  of  air  (compressed)  required  to  siqoply  the 
initial  pressure  and  leakage  is  pumped,  preferably,  into  a reservoir,  from  which  the  air  passes 
through  check  valves  (one  check  valve  for  each  working  cylinder)  into  the  engine,  and  a lever 
safety  valve  is  attached  to  the  reservoir  as  a means  of  controlling  the  initial  pressure  of  the 
air  used. 

SPECIAL  ADVANTAGES  DUE  TO  CONSTRUCTION. 

The  working  pistons  being  connected  by  means  of  a beam,  are  therefore  counterbalanced. 
The  displacer  pistons  are  counterbalanced  in  a like  manner.  The  temperature  of  the  surfaces 
against  which  the  metallic  i)acking  rings  of  the  displacer  pistons  slide,  is  about  90'^  I'.,  and  the 
temperature  of  the  surfaces  against  which  the  metallic  packing  rings  of  the  working  jnstons  slide, 
is  about  180°  F.  All  the  pistons  operating  in  vertical  lines  wear  the  cxlinders  evenly,  and  by 
reason  of  their  vertical  positions  they  require  the  minimum  amount  of  set  to  the  packing  rings, 
and  the  consequent  friction  of  the  pistons  is  reduced  to  the  smallest  amount  possible.  There- 
fore, for  the  reasons  above  given,  and  also  that  there  is  no  exhaust,  the  amount  of  oil  required 
to  lubricate  the  pistons  is  reduced  to  a minimum  quantity. 


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FIGURE  2. 


FIGURE  3. 


Air  Hngine  Xest. 

By  Geo.  H.  Barrus,  M.  E. 


Mr.  JOSHUA  MERRILL,  Treasurer, 

OF  THE 

Woodbury,  Merrill,  Patten,  & Woodbury  Air  Eugiue  Co., 

8 Exchange  Place,  Boston,  Mass. 


Dear  Sir  ; 

Having  made  at  your  request  a series  of  tests  on  the  No.  13  Woodbury,  Merrill, 
Patten,  & Woodbury  Air  Engine,  at  your  works  in  South  Boston,  the  object  of  which 
was  to  determine  the  economy  as  to  consumption  of  fuel  with  which  the  engine  works,  I 
beg  to  submit  the  following  table,  a brief  summary  of  the  principal  results  of  the  same. 
A description  of  the  engine,  and  the  method  of  conducting  the  tests,  together  with  a full 
record  of  the  results,  is  given  in  a detailed  report,  which  I will  submit  at  an  early  day. 

On  all  the  tests  except  the  last,  the  principal  load  on  the  engine,  consisted  of  a 
No.  35  Sturtevant  Exhausting  P’an,  with  72  inch  case,  which  makes  535  revolutions  per 
minute  when  the  engine  makes  iio  revolutions  per  minute.  On  the  last  test,  the  principal 
load  consisted  of  the  same  fan,  and  in  addition,  a Sturtevant  P'an,  with  60  inch  case,  No- 
123,  which  made  about  625  revolutions  per  minute.  The  friction  of  the  engine  was  deter- 
mined by  subtracting  the  average  power  absorbed  by  a Prony  Brake,  applied  to  the  fi}'-wheel, 
from  the  indicated  Horse  Power  developed  at  the  same  time,  on  the  occasion  of  supplementary 
tests,  a part  of  which  were  made  March  7th,  and  a part,  March  22nd,  the  number  of  these 
tests  being  fourteen.  The  average  Indicated  Horse  Power  was  31.18,  and  the  average  Brake 
Horse  Power,  19.92 

It  appears  from  the  table,  taking  the  test  of  March  23rd  as  a proper  indication  of 
the  performance  of  the  engine,  that  the  amount  of  coke  used  in  a ten  hours  run,  including 

the  wood  and  coke  required  to  start  the  fire,  beginning  with  a cold  engine,  was  1.91  lbs. 

per  Indicated  Horse  Power  per  hour,  and  2.98  lbs.  per  Brake  Horse  Power  per  hour.  On 

the  same  test,  for  a period  of  hours,  after  the  engine  had  attained  its  normal  conditions 

of  work,  the  quantity  of  coke  consumed  was  1.54  lbs.  per  indicated  Horse  Power  per  hour, 
and  2.37  lbs.  per  Brake  Horse  Power  per  hour.  During  the  test  of 'March  6th,  the  quantity 
of  water  which  passed  through  the  Coolers  amounted  to  an  average  of  3612  lbs.  per  hour, 
which  is  equivalent  to  7.2  gallons  per  minute.  This  water  was  supplied  at  a temperature 
of  36  degrees,  and  discharged  at  a temperature  of  102.8  degrees. 


I do  not  regard  these  results  as  the  best  that  can  be  obtained  from  the  engine,  for 
there  is  a consideral)le  loss  of  heat  from  the  unprotected  exterior  surfaces  of  the  Furnaces, 
due  to  radiation,  which  can  easily  be  prevented  by  the  use  of  suitable  covering. 

Taking  the  results  as  they  stand,  however,  the  consumption  of  fuel  per  Effective  Horse 
Power  transmitted  through  the  belt,  is  not  more  than  one-half  of  that  required  for  the  best 
non  condensing  steam  engines  of  small  power,  which  are  commonly  used. 

It  appears  to  me  that  the  engine,  in  its  present  shape,  may  be  successfully  placed  on 

the  market,  with  the  assurance  of  satisfactory  results  in  practical  operation,  and  I believe 

that  its  economy  in  the  consumption  of  fuel  and  entire  safety  will  commend  it  to  any 
person  requiring  motive  power. 

In  view  of  the  very  large  improvement  that  has  already  been  made  in  the  econom}'  of 
the  engine,  and  in  view  of  the  evident  losses  which  have  been  referred  to,  which  are  still  going 
on,  it  seems  quite  probable  that  an  engine  of  this  type  can  be  made  which  will  develop  an  indi- 
cated Horse  Power  on  a consumption  of  i lb.  of  coal  per  hour ; measuring  the  coal  during  a 
period  beginning  with  the  fires  in  a normal  condition,  and  ending  with  the  fires  in  the  same 
condition.  This  is  one-third  less  than  the  results  of  the  test  of  March  23d,  giving  1.5  lbs.  of 
coal  per  indicated  Horse  Power  per  hour. 

I am,  P^aithfully  yours, 

GEO.  H.  BARRUS, 

E.xpert  and  Consulting  Steam  Engineer, 


March  29,  1S89. 


No.  95  Milk  St.,  Boston. 


I.  KIND  OF  FUEL. 

*'G.\.S  HOUSE  COKE. 

( iLori.i '.s  ('leek 
Cuiiiberliiiui 
( 'o:il. 

2 

1 )ate  of  Test.  i S89. 

Mar.  5. 

Mar.  6. 

Mar.  23. 

Mar.  23. 

-Mar.  25. 

n 

0- 

Duration  ....  hrs. 

7- 

8.25 

10. 

6.25 

5- 

4. 

Condition  of  fire  at 
beoinnino-  and  end. 

0 0 

Normal. 

liegin  with  New 
Fire. 

Find  with  Fire 
burned  out. 

Kegin  with  New 
Fire. 

End  with  Fire 
burned  out. 

Normal. 

Normal. 

5- 

Weight  of  dry  fuel 
burned,  including  4-10 
of  weight  of  wood 
used  for  lighting  fire 
lbs. 

342. 

453-6 

601.6 

314- 

262. 

6. 

Weight  of  dry  fuel 
burned  per  hour  lbs. 

48.9 

55- 

60.2 

50. 

52-5 

7- 

Indicated  H.  P.  devel- 
oped by  engine,  I.H.P. 

30.16 

29.68 

31-45 

32-38 

32.43 

8. 

Revolutions  per  min. 

113-1 

1 1 2.4 

1 1 2.5 

113-6 

108.4 

9- 

P'uel  burned  per  I.H.P. 
per  hour  lbs.  I 

1.62 

1.85 

1.91 

1-54 

i 1 

1 

1.62 

10. 

P'uel  burned  per  Brake 
H.P.  per  hour,  assum- 
ing friction  of  11.26 
HA\ 

2-59 

2-99 

2.98 

2-37 

1 

i 2.48 

*0n  the  test  of  INIarch  5th,  the  coke  when  fired,  contained  20%  of  moisture,  and  on 
that  of  March  6th,  14.2%  of  moisture,  determined  by  drying  samples. 

On  the  test  of  March  23rd,  the  coke  when  fired,  was  dry. 


Testimonials. 


Established  1S45. 

HANCOCK  cN  ALLEN, 

Successors  to  Ozro  Hancock, 

Mr.  Josht-A  Merrill,  Treasurer,  Winxhexdox,  Mass.,  March  5th,  1889. 

Woodbury,  Merrill,  Patten  & Woodbury  Air  Engine  Co., 

8 E.xchange  Place,  Boston,  Mass. 

Dear  Sir, — Having  for  the  past  five  years  used  one  of  your  Air  Engines,  I gladly  certify  that 
it  has  proved  most  e.xcellent,  in  every  respect,  as  a motor.  The  consumption  of  fuel  has  never  exceeded 
350  lbs.  per  day,  including  the  starting  fires.  The  engine  requiring  very  little  attention,  the  engineer 
being  able  to  do  at  least  three-quarters  of  a day's  work  at  tools,  besides  caring  for  the  engine.  The 
power  being  steady  and  uniform,  no  apprehension  of  danger  to  trouble  us,  and,  in  short,  I consider  it 
a most  valuable  and  reliable  motor.  Since  putting  in  our  new  engine  of  an  improved  make,  we  are 
using  2^0  lbs.  only  of  bituminous  coal,  with  a small  amount  of  spent  tan  bark  in  combination.  This 
includes  the  starting  coal,  or  the  entire  consumption  for  the  day,  the  engine  indicating  about  14  Horse 
Power,  and,  to  drive  our  entire  machinery,  requiring  at  least  10  delivered  Horse  Power.  The  engine 
runs  beautifully;  steady  motion;  regulates  as  closely  as  the  best  steam  engine,  and  is  most  satisfactory 
in  every  particular.  I feel  you  will  have  great  success  in  the  sale  of  this  engine  to  all  people  requiring 
power,  and  I wish  you  the  success  so  hne  an  invention  is  worthy  of. 

I am,  respectfully  yours, 

JoHX  Haxcock, 

Of  the  firm  of  Hancock  & Allen. 


Mr.  Joshua  Merrill,  Treasurer,  31  Milk  Street.  Boston’,  April  6,  1889. 

Woodbury,  Merrill,  Patten  &:  Woodbury  Air  Engine  Co., 

8 Exchange  Place,  Boston,  Mass. 

Dear  Sir,  — In  reply  to  your  inquiry,  I have  seen  the  various  air  engines  invented  by  yourself 
and  associates,  and  have  taken  note  of  the  continued  improvements  added  from  time  to  time  for  several 
years,  and  therefore  am  able  to  express  my  confidence  in  their  practical  operation,  safety  from  explo- 
sions, and  economy  in  fuel. 

Yours  very  truly,  C.  J.  H.  Woodbury 


M.  C.  Bullock,  Pres.  Geo.  Woodland,  Treas.  O.  H.  Blanke,  Sec'y.  J.  S.  Lane,  Gen'l  Supt, 

M.  C.  BULLOCK  MANF’G  CO., 

Phenix  Huilding,  No.  138  Jackson  Strcef. 

Works : Lake  St.  and  Talman  Avenue. 

Mr.  Joshua  Merrill,  Treasurer,  Chicago,  U.  S.  A.,  April  15,  1889. 

Woodbury,  Merrill,  Patten  N:  Woodbury  Air  Engine  Co., 

8 BLxchange  Place,  Boston,  Mass. 

Dear  Sir, — Replying  to  your  favor  of  the  iith,  I beg  to  acknowledge,  not  only  your  very  kind 
letter,  but  also  the  report  of  the  tests  made  by  Geo.  H.  Barrus,  on  the  Woodbury,  Merrill,  Patten  &: 
Woodbury  Air  Engine.  1 have  examined  the  tests  very  carefully,  and  am  more  than  pleased  with  the 
results,  and  I wish  to  congratulate  you  most  heartily  upon  the  advance  which  you  have  made  in 
perfecting  this  remarkable  engineering  problem. 

With  kind  regards,  and  wishing  you  the  success  which  you  so  richly  deserve,  I am. 

Yours  very  sincerely,  M.  C.  Bullock,  Frcs't. 


I).  M WrsTuN,  Pr^s.  W’m.  ( ).  LiNcoi.N.  Treats.  Hhnj.  1-  . Rai>foki>,  Gfn. 

■J’HE  AMERICAN  'I'OOI.  N:  MAC'HINE  CO.. 

Kingston  Street, 

Mr.  Joshu.v  Merrill,  'Irtasurcr.  Uu.sidn.  M.\s.s.,  April  25,  18S9. 

Woodbury,  Merrill,  Ratten  N Woodbury  Air  Engine  Co., 

8 Exchange  Rlace,  Roston,  .Mass. 

1)e.\r  Sir,  — Ha\'ing  carefully  read  the  report,  by  Mr.  Rarrus,  of  se\'eral  trials  of  }'our  engine, 
made  for  the  purpose  of  ascertaining  its  economy  in  the  consumption  of  fuel,  and  ha\’ing  seen  this 
engine  in  operation,  I am  quite  of  the  opinion  that  it  is  to  be  the  motor  of  the  future,  where  not 
exceeding  75  to  100  Horse  Rower  is  required. 

Yours  very  truly, 

Renj.  P'.  R.\dford, 

General  ^^anagel■  The  .\merican  Tool  & Machine  Co. 


'I'lIE  'I'AHNTON  LOCOMOTIVE  MEG.  CO. 

\Vm.  R.  Hii.i.ings,  Agent  and  Treasurer. 

Mr.  Joshu.a.  Merrill,  Trcasu7-er.  T.xun'ton,  Mass.,  April  27,  1889. 

Woodbury,  Merrill,  Ratten  &:  Woodbury  Air  Engine  Co., 

8 Exchange  Rlace,  Roston,  Mass. 

Dear  Sir,  — In  reply  to  your  request  for  an  expression  of  our  views  upon  certain  points  con- 
nected with  your  Air  Engine,  we  take  pleasure  in  saying  that  we  have  examined  on  several  occasions, 
and  with  considerable  care,  the  engine  now  in  operation  at  South  Roston;  that  we  believe  that  this 
engine  marks  an  important  advance  in  the  progress  of  the  Air  Engine  towards  practical  perfection  ; that 
the  economy  of  fuel,  indicated  by  the  tests  made  by  Mr.  Rarrus  and  others,  is  remarkable,  and  that  we 
are  ready  to  make  arrangements  with  you  for  the  construction  of  your  Air  Engine,  of  such  sizes  as  you 
may  name  and  from  such  patterns  and  drawings  as  you  may  furnish. 

Yours  very  truly, 

'Ral'nton  Locomotive  Meg.  Co. 

Hy  Wm.  R.  Billings,  Agt.  and  Treas. 


Col.  Franklin  Fairbanks,  Prest.  E.  K.  Whitney.  I'ice  Pres.  P.  F.  Hazen,  Sec''y^  St.  Johnsbury,  \'crmont. 

W.  P.  Fairbanks,  Treas.  W'arren  S.  Mili-,  CJt.  Ex.  Cant.  E.  A.  Mildank,  Afgr.^  i6i  Franklin  Si.,  Poston. 

STAX1).\R1)  ELECTRIC  COMRAXY,  of  Vermo.xt. 

(Whitney  System.) 

Manufactured  by  llie  E.  & T.  f'AIRHAXKS  & CO.,  St.  Jolinsbury,  Vt. 

Mr.  Joshua  Merrill,  Treasurer,  Bo.ston,  Mass.,  April  30.  1888. 

Woodbury,  Merrill,  Ratten  & Woodbury  Air  Engine  Co.. 

8 Exchange  Rlace,  Roston,  Mass. 

Dear  Sir,  — iMy  continued  absence  from  Roston  has  alone  prevented  my  calling  on  you  during 
the  past  two  weeks.  There  are  several  parties  who  are  interested  in  the  reports  of  the  tests  made  on 
your  engine,  and  it  is  my  intention  to  accompany  them  when  they  make  their  inspection.  If  they  see 
the  engine  as  I have  seen  it,  there  is  no  doubt  about  their  verdict.  It  is  hard  to  convince  anyone  that 
there  is  an  air  engine  of  any  practical  use.  that  is.  an  engine  capable  of  delivering  any  considerable 
amount  of  power, — 20  or  30  Horse  Power,  for  instance.  Seeing  is  believing,  however,  and  the  most 
skeptical  must  give  way  after  investigaiing  your  motor.  Rroving  as  you  do  that  a Horse  Rower  may  be 
delivered  with  an  expenditure  of  2.37  lbs.  of  coal  per  hour,  and  that  result  accomplished  without  boiler 
or  steam,  you  must  attract  the  attention  of  the  power  using  public.  For  use  in  hotels  and  apartment 
houses,  where  electric  lighting  machinery  or  ventilating  apparatus  may  be  required,  your  engine  is 
particularly  well  adapted.  Again,  in  locations  where  the  use  of  steam  is  imjjossible  on  account  of  lack 
of  boiler  room,  you  stand  ready  to  supply  the  situation.  I am  convinced  that  the  Air  Engine,  in  the 
present  form,  constructed  by  your  company,  is  a motor  of  decided  value,  not  alone  on  account  of  its 
economy  but  also  on  the  score  of  safety. 

^'ery  truly  yours. 

^\^^I.  C.  ^^'ooPWARD.  Eleetrieal  Engineer. 


GRANT  LOCOMOTIVE  WORKS. 

New  York  Office,  ^3  Wall  Si. 

Mk.  Jo.sHiA  Merrill,  Treasurer,  Paterson,  N.  J.,  April  i6,  1889. 

Woodburv,  Merrill.  Patten  &;  M’oobury  Air  Engine  Co., 

8 Exchange  Place,  Poston,  Mass. 

Dear  Sir.  — Yours  of  nth  inst..  with  report  of  the  tests  of  your  Air  Engine,  by  Mr.  Barrus,  M.E., 
to  hand.  1 have  read  it  with  interest,  and  can  see  no  reason  why  your  engine  should  not  have  a large 
sale  as  soon  as  you  are  ready  to  put  it  on  the  market.  Respectfully,  W.  W.  Evans,  Sup't. 


THOMSON-HOUSTON  ELECTRIC  CO. 

ELECTRIC  LIGHTING  AND  POWER. 

Works,  Lynn,  Mass.  Principal  Office,  620  Atlantic  Ave.,  Boston.  Western  Office,  148  Michigan  Ave,  Chicago. 

Mr.  Joshua  Merrill,  Treasurer,  Boston,  May  3,  1889. 

Woodbury,  Merrill,  Patten  & Woodbury  Air  Engine  Co., 

8 Exchange  Place,  Boston,  Mass. 

Dear  Sir,  — In  accordance  with  your  request,  I desire  to  submit  my  opinion  regarding  your  new 
Air  Engine,  1 have  been  very  much  interested  in  reading  the  report  of  Mr.  Barrus  in  regard  to  the 
test  made  on  same  by  him,  and  was  largely  influenced  by  reading  these  reports  to  go  and  make  a 
personal  examination  of  the  30  Horse  Power  Engine  now  completed. 

It  is  my  opinion,  based  upon  some  little  experience  in  steam  engineering,  that  in  this  engine  you 
have  made  a decided  step  in  advance  on  the  subject  of  air  engines.  I am  confident  that  in  this  you 

have  a perfect,-  practical,  and  exceedingly  economical  engine ; and  should  you  decide  to  construct  a 

100  Horse  Power  for  your  first  size,  you  may  consider  that  you  have  an  order  for  one  from  this  company. 

Very  truly  yours. 

Engineering  Department  Thomson-Houston  Electric  Co. 

H.  C.  Patterson,  Elec. 

.Mr.  Joshua  Merrill,  Treasurer,  Boston,  May  3,  1889. 

Woodbury,  Merrill,  Patten  &:  Woodbury  Air  Engine  Co., 

8 Exchange  Place,  Boston,  Mass. 

Dear  Sir, — In  the  year  1877,  as  manager  of  the  Nashua  Iron  &:  Steel  Co.,  I made  an  arrange- 
ment witli  you  to  manufacture  the  first  experimental  engine,  to  be  propelled  by  means  of  the  heating 

and  the  cooling,  in  rapid  succession,  of  the  air  confined  within  the  cylinders  and  “heater”  of  the 
macliine.  So  much  success  was  secured  at  that  time  as  to  give  me  an  earnest  of  very  promising  results 
to  come,  and  consequently,  I have,  from  time  to  time,  become  somewhat  familiar  with  the  successive 
improvements  you  have  added  to  the  engine.  On  my  last  visit  to  the  machine,  a few  days  ago,  I was 
more  tlian  ever  impressed  with  the  perfection  of  the  motor,  its  simplicity,  its  reliable  efficiency  as  to 
power,  its  smoothness  and  regularity  of  motion,  and  the  ease  with  which  it  is  managed.  I am  convinced 
that  you  have  made  very  great  strides  towards  a safe,  efficient,  and  reliable  means  of  motion,  and  have 
no  doubt  tlie  engine  will,  in  large  degree,  supersede  the  use  of  steam  as  a means  of  mechanical  power. 
1 hope  your  perseverance  and  large  outlay  will  be  fully  rewarded. 

Truly,  &c.,  Moses  A.  Herrick. 
WRIGirr  ELECTRICAL  ENGINEERING  CO., 

7.(  FEDERAL  STREET, 

Alex.  P.  Wright,  Managing  Director. 

Mr.  JdsHUA  Merrii.l.  Treasurer,  Bo-STON,  IMass.,  U.  S.  A.,  May  4th,  1889. 

Woodburv,  Merrill,  Patten  & Woodbury  Air  Engine  Co., 

8 Exchange  Place,  Boston,  Mass. 

Dear  Sir, — I was  much  interested  during  my  visit  to  see  your  Air  Engine,  and  have  given  it 
considerable  thought  since.  If  it  will  come  up  to  the  claims  made  for  it,  and  I believe  it  will  do  so 
and  more,  wiien  suitable  sizes  are  ready  for  the  market,  the  field  for  its  application  in  Electric  Lighting 
will  be  \ery  wide,  and  it  will  undoubtedly  come  into  use  to  a large  extent  for  this  purpose. 

Vours  truly,  Alex.  P.  Wright, 

Expert  Coitsultiiig  and  Electrical  Engineer. 


Quotations  from  various  Authorities  with  Explanatory  Notes. 


The  theoretical  ad\'antat;'e.s  of  air  as  a safe  and  economical  ag'ent  for  converting  heat 
into  power  have  long  been  recognized  by  scientists  and  mechanicians  ; but  efforts,  to  use 
it  practically,  have  been  attended,  hitherto,  with  such  great  difficulties,  as  to  i)revent  its 
general  adoption  as  a motor. 

But,  notwithstanding  the  obstacles  have  aijpeared  excessive,  the  most  eminent  authorities 
on  mechanics  have  been  confident  that  air  is  destined,  to  supersede  steam. 

Appleton’s  Cyclopa'dia  of  Applied  Mechanics,  vol.  I.,  page  620,  published  in  1880,  states: 

“The  engines  that  have  just  been  described  are  necessarily  limited  to  comparatively  low  pres- 
sures, and  hence  must  be  very  bulky  when  designed  to  develope  considerable  power.  This  limitation 

is  an  essential  condition  of  their  design,  because  the  original  pressure  of  the  air  which  is  compressed 
and  heated  is  that  of  the  atmosphere.  If,  however,  the  working  air  be  confined  in  the  machine, 
and  originally  compressed  to  a high  pressure,  this  difficulty  disappears.  Thus,  suppose  it  is  found 
practicable  to  maintain  a temperature  in  a given  air-engine  sufficient  to  double  the  original  pressure 
of  the  air.  Then,  if  the  air  were  admitted  at  the  pressure  of  the  atmosphere,  the  available  pres- 
sure, after  heating,  would  be  about  15  lbs.  per  square  inch.  But  if  the  supply  of  air  were  drawn 
from  a reservoir,  in  which  the  pressure  was  60  lbs.  per  square  inch,  the  effect  of  increasing  the 

temperature  to  the  same  point  as  in  the  former  case  would  be  to  double  the  original  pressure, 
making  1 20  lbs.  per  square  inch.  It  seems  strange  that  the  majority  of  inventors  should  have 
ignored  this  significant  principle.” 

IIV  employ  this  principle  of  using  air  compressed  to  a pressnre  of  60  lbs.  per  square  inch. 

And  on  page  623  the  following  occurs  : 

“ It  has  been  predicted  by  more  than  one  prominent  engineer  that  the  steam  engine  will  vet 
be  superseded  by  the  air  engine.” 

In  a work  by  a well  known  writer,  John  Bourne,  entitled  “Recent  Improvements  in  the  Steam 
Engine,”  published  in  London,  in  1874,  on  page  330,  he  states  : 

“ The  wasteful  character  of  the  steam  engine  as  a source  of  motive  power,  has  now  become 

so  widely  known  that  public  attention  has  been  directed  with  more  ardor  than  heretofore,  to  the 

discovery  of  expedients  for  its  supersession.  Of  these  alternative  expedients,  the  most  promising 
seems  to  be  some  form  of  air  or  gas  engine.  But  all  the  air  and  gas  engines,  heretofore  devised, 

labor  under  this  radical  defect,  that  only  low  pressures  can  be  employed  in  them,  and  hence  only 

a portion  of  the  energy  of  the  heat  can  be  transformed  into  power.  So  soon  as  this  fault  shall 

have  been  corrected,  without  the  introduction  of  other  sources  of  loss,  the  steam  engine  will  be 
superseded ; and  there  are  good  grounds  for  concluding  that  this  result  is  not  far  distant,  but  will 
soon  be  achieved.” 

We  have  remedied  this  defect,  unthont  the  introduction  of  other  sources  of  loss. 

Knight’s  American  Mechanical  Dictionary,  published  in  1874,  vol.  I,  page  35.  states: 

“ In  this  engine  the  air  received  heat  at  the  temperature  of  650°  Fah.,  and  discharged  the 
lost  heat  at  that  of  150*^  Fah.  The  efficiency  of  a theoretically  perfect  engine,  with  those  limits  of 
temperature,  would  be  0.45,  and  its  consumption  of  coal  0.73  of  a lb.  per  horse-power  per  hour. 


The  actual  consumption  of  coal  per  horse-power  per  hour  was  about  2.2  lbs.,  being  three  times  the 
consumption  of  a theoretically  perfect  engine,  and  corresponding  to  an  actual  efficiency  of  0.15  or 
one-third  of  the  maximum  theoretical  efficiency. 

The  following  is  a comparison  of  the  consumption  of  bituminous  coal  of  specified  quality,  per 
horse-power  per  hour  : 

1.  For  a theoretically  perfect  engine,  working  between  such  limits  of  temperature  as  is  usual 
in  a steam  engine,  1.86  lbs. 

2.  For  a double  acting  steam  engine,  impelled  to  the  utmost  probable  extent,  2.50  lbs. 

3.  For  a well  constructed  and  properly  worked  ordinary  steam  engine,  on  an  average,  4.00  lbs. 

Referring  to  above,  especially  to  paragraph  3,  ivc  direct  yotir  attention  to  the  fact,  that  as 
per  test  of  George  H.  Barms,  herezuith  submitted,  the  consumption  of  coal  per  horsc-pozver  per  hour 
of  our  engine  is  but  1.54  lbs. 

Science  has  thoroughly  demonstrated  the  theoretical  economy  of  heat  which  results  from  the 
use  of  the  regenerator.  Rankine  in  his  ‘‘  Manual  of  the  Steam  Engine  and  other  prime  movers,” 

published  in  London,  in  1876,  states  on  page  353  : 

" By  thus  storing  and  re-storing  a certain  quantity  of  heat,  the  alternate  lowering  and  raising 
of  the  temperature  of  the  air  is  effected  without  the  expediture  for  that  purpose  of  any  heat  from 
the  furnace,  except  such  as  is  requried  to  supply  the  waste  of  heat  that  occurs  in  the  regenerator ; 
that  waste,  according  to  experiment,  being  from  one-tenth  to  one  one-tzoentieth  of  the  whole  quantity 
of  heat  required  to  raise  the  temperature  of  the  air  at  each  stroke.” 

Our  engine  is  provided  zvith  the  most  perfect  regenerator  ever  made,  by  the  use  of  zuhieh,  zve 
obtain  the  highest  eeononiical  results. 


Engines  of  the  following  sizes  will  be  constructed  and  put  upon  the 
market  with  as  little  delay  as  possible:  — 


Xo. 

r ) . 

K i V e Horse  T^o  we  r . 

Xo. 

10. 

Kifteen  Horse  I^cower. 

Xo. 

lo . 

Tloirt\"  Hive  Horse  Hower. 

Xo. 

20. 

Si^t3"  Horse  Hower. 

Xo. 

2o. 

Oivie  Hiuodrecl  Horse  F*o\\^er 

The  rapid  advance  lately  made  in  the  economy  of  this  engine  has  con- 
vinced the  inventors  from  the  data  they  have  developed,  that  there  is  no  doubt 
but  that  engine  number  25,  and  probably  number  20,  will  run  on  i lb.  of  coal 
per  Indicated  Horse  Power  per  hour,  and  1.6  lbs.  per  Delivered  Horse  Power 
per  hour. 

A large  number  of  orders  for  engines  of  various  sizes,  to  be  delivered  as 
soon  as  they  can  be  constructed,  are  already  offered  to  the  Company. 


i 


•1* 


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